Sanding Dust Interfering with Finish

Tips on prevention and cure when sanding dust messes up a lacquer spray job. June 9, 2007

While I was spraying dark (almost black) wood, sanding dust got stuck in the deep grain of the wood I was finishing. Usually the sanding dust that sticks in the wood grain disappears when I shoot the next coat on a lighter wood (i.e. cherry, oak, birch, etc.), but in this situation, the white dust showed through the topcoat. How can I fix this problem, and prevent this in the future?

Forum Responses
(Finishing Forum)
From contributor B:
My guess is that you've got more dust than the wet coat can melt. For now, see about spraying some aerosol retarder and see if that will fix the problem. In the future, try to blow the dust off before spraying the next coat.

From contributor S:
I agree that if it's sanding dust, it should melt into the next coat of finish, especially if you use retarder. If that doesn't do it, it's likely something else.

From contributor V:
Take a slightly damp rag with lacquer thinner, squeeze it out and use it as a tack rag. Move fast, like French polishing speed. Don't stop your movement. Blow gun, dust with hand, and air - makes great tack rag - then spray.

From contributor J:
All I use for tacking now is Endust on a clean rag. Try it - you'll be amazed; it pulls all the dust out of those pores and removes the static too. Nothing works better. I use it on my car painting too. It leaves no residue.

From contributor K:
I would have thought Endust would cause finishing problems. Not sure I want to risk trying it myself, but an interesting solution. I wonder what's in Endust?

From contributor J:
No wax or grease or anything that can cause fish-eyes. I've been using it for over 10 years now, for cabinets and cars. It works so much better.

From contributor O:
It is true that Endust contains no silicone or mineral oils. In fact, it is recommended for use on wooden artifacts in museum collections.

From contributor L:
Just an interesting side note. Endust contains 20% parrifinic oil which is the same stuff used in automotive transmission fluid and Slick 50 motor oil.

From contributor R:
Thank you for the MSDS on Endust. Now I will have something to show my customers when they ask (after I have recommended they use it), what's in that stuff?

From contributor Y:
In ML Campbell's Agualente wb lacquer, one of the ingredients is paraffin wax…?

From contributor P:
Spray two coats of finish reduced 1 part finish to 1 part solvent, plus the maximum amount of retarder recommended by the manufacturer. Spray the coats back to back as wet as possible, re-wet the trapped solvents. If it is a catalyzed finish that has fully cured, try a test on a door back to make sure the finish doesn't wrinkle. The Endust trick blows me away. I can't wait to try it, thanks for the tip.